Locoregional Control Benefit of a Tumor Bed Boost for Ductal Carcinoma In Situ (DCIS)

PURPOSE/OBJECTIVE(S)

Radiotherapy (RT) following breast conserving surgery (BCS) for ductal carcinoma in situ (DCIS) reduces invasive and in situ recurrences. Whereas landmark studies suggest that a tumor bed boost improves local control for invasive breast cancer, the benefit in DCIS remains less certain. We evaluated outcomes of DCIS patients treated with or without a boost and hypothesized that a tumor bed boost would improve locoregional control rates.

MATERIALS/METHODS

The study cohort comprised patients with DCIS who underwent BCS at our institution from 2004-2018. Clinicopathologic features, treatment parameters and outcomes were ascertained from medical records. Patient and tumor characteristics were evaluated relative to outcomes using univariable and multivariable Cox models. Recurrence-free survival (RFS) estimates were generated using the Kaplan Meier method.

RESULTS

We identified 1675 patients who underwent BCS for DCIS (median age 56 [interquartile range (IQR) 49, 64]). Boost RT was employed in 68% of cases (n = 1146) and endocrine therapy in 32% (n = 536). At a median follow-up of 4.2 years (IQR 1.4, 7.0), we observed 61 locoregional recurrence events (56 local, 5 regional) and 21 deaths. Univariable logistic regression demonstrated that boost RT was more common among younger patients (p<0.001) with positive/close margins (p<0.001), and with larger tumors (p<0.001) of higher grade (p = 0.025). The 10-year RFS rate was 88.8% among those receiving a boost and 84.3% among those without a boost (p = 0.3), and neither univariable nor multivariable analyses revealed an association between boost RT and locoregional recurrence.

CONCLUSION

Among patients with DCIS who underwent BCS, use of a tumor bed boost was not associated with locoregional recurrence or RFS. Despite a preponderance of adverse features among the boost cohort, outcomes were similar to those not receiving a boost, suggesting that a boost may mitigate risk of recurrence among patients with high-risk features. Ongoing studies will elucidate the extent to which a tumor bed boost influences disease control rates.

Accelerated Partial Breast Irradiation (APBI) For HER2+ Early-Stage Breast Cancer

PURPOSE/OBJECTIVE(S)

Historically, HER2+ breast cancer exhibited poor outcomes and, hence, has not been well-studied among trials of accelerated partial breast irradiation (APBI). We hypothesized that in contemporary practice with effective HER2-targeted agents, patients with HER2+ breast cancer now have excellent disease control and survival outcomes when treated with adjuvant APBI.

MATERIALS/METHODS

Using a prospectively-maintained institutional database, we identified all HER2+ breast cancer patients treated with breast conserving surgery (BCS) and adjuvant APBI from 2000 - 2022. Salient clinicopathologic parameters were collected, as were receipt of systemic and endocrine therapies. All patients received external beam APBI to a total dose of 40Gy in 10 daily fractions over 2 weeks. We analyzed outcomes including local recurrence (LR), regional recurrence, distant recurrence, and death. Cumulative incidence functions were calculated to estimate the incidence of LR with the competing risk of death. All statistical analyses were performed in R version 4.2.2.

RESULTS

The study cohort comprised 52 patients with HER2+ breast cancer (median age 64 years; range 44-87). Nearly all had T1 tumors (98%; median size 15 mm; range 1 - 21 mm). Approximately 10% had multifocal disease, with one exhibiting suspicion for lymphovascular invasion. Most patients had ER+ disease (88%). All patients had negative final surgical margins. Nearly all underwent sentinel node biopsy (94%), with the remainder undergoing no surgical axillary evaluation. 42 (81%) received chemotherapy, 40 (77%) endocrine therapy, and 42 (81%) HER2-directed therapy, most commonly trastuzumab. At 143.8 person-years of follow-up (range 7 - 226 months for each patient), we observed two LR events, at 14 and 26 months, yielding a 2-year LR rate of 3.8%. No regional or distant recurrences were observed, nor were any contralateral invasive breast cancer events or breast-specific mortality events. Two deaths were noted in the cohort, both without evidence of disease.

CONCLUSION

Among a cohort of HER2+ early-stage breast cancer patients managed with BCS and APBI, we observed a 2-year LR rate of 3.8% with no regional or distant recurrences, and excellent overall survival. These findings merit longer term follow-up among larger cohorts, although are thus far consistent with the results of contemporary randomized trials of APBI unselected for HER2-status.

Oncotype Recurrence Score (RS) at the Extremes of Tumor Size: Which Drives Clinical Outcomes?

PURPOSE/OBJECTIVE(S)

Tumor size is an established and independent risk factor for local-regional recurrence (LRR) and distant recurrence (DM). More recently, the recurrence score calculated from a 21-gene expression assay (Oncotype DXTM, Exact Sciences) has also been correlated with LRR and DM. We sought to determine the impact of the interaction between tumor size and Oncotype RS, particularly when the variables are in discrepancy with each other. More specifically, we evaluated clinical outcomes in patients with small tumors (≤1 cm) and high RS (≥26) and, separately, in patients with large tumors (>5 cm) with low RS.

MATERIALS/METHODS

Between 2008 and 2020, 310 patients were identified retrospectively as having been treated for early-stage, hormone-receptor positive, Her2-negative breast cancers with tumor size ≤1 cm that were node-negative and had RS ≥ 26 at our institution. In addition, 64 patients were identified with tumor size >5 cm and RS < 26 (irrespective of nodal status). Locoregional recurrence rates (LRR) and invasive recurrence rates (composite of LRR and distant recurrence) were estimated using the Kaplan-Meier method.

RESULTS

Patient characteristics are shown in Table 1. In the group of patients with small tumors and high RS, the 5- and 10-year invasive recurrence rates with 95% CI were 8% (4.2-12) and 17% (8.2-26). The 5- and 10-year locoregional recurrence rates with 95% CI were 5.8% (2.7-8.8) and 15% (6.2-23). In the group of patients with large tumors and low RS, 10-year rates could not be estimated with the available data. The 5- and 8-year invasive recurrence rates with 95% CI were 3.2% (0-7.5) and 3.2% (0-7.5). The 5- and 8-year locoregional recurrence rates with 95% CI were 1.6% (0-4.7) and 1.6% (0-4.7).

CONCLUSION

Our findings suggest that patients with small tumors and high RS are at a higher risk for LRR compared to the average ≤1 cm node-negative breast cancer based on published data on the effect of tumor size on LRR and DM. Similarly, tumors larger than 5 cm with low RS appear to behave indolently and in a manner consistent with more favorable risk (despite their large size). These findings may have important implications for the tailoring of local-regional treatment strategies.

A concept of a broadband inverted geometry spectrometer for the Second Target Station at the Spallation Neutron Source

BWAVES is an acronym for Broadband Wide-Angle VElocity Selector spectrometer, indicating that a novel WAVES (Wide-Angle VElocity Selector) device will be used to select the velocity/wavelength of the detected neutrons after they are scattered by the sample. We describe a conceptual design of BWAVES, a time-of-flight broadband inverted-geometry neutron spectrometer for the Second Target Station at the Spallation Neutron Source operated by Oak Ridge National Laboratory. Being the first inverted geometry spectrometer where the energy of the detected neutrons can be chosen by a WAVES device mechanically, irrespective of the limitations imposed by the crystal analyzers or filters, BWAVES will feature a uniquely broad, continuous dynamic range of measurable energy transfers, spanning 4.5 decades. This will enable measurements of both vibrational and relaxational excitations within the same, continuous scattering spectra. Novel approaches that are necessary for the implementation of a WAVES device at the BWAVES spectrometer will result in a spectrometer with the design and characteristics much different from those displayed by the neutron spectrometers in existence today.

Usefulness of Restaging Pelvis Magnetic Resonance Imaging After Neoadjuvant Concurrent Chemoradiotherapy in Patients With Locally Advanced Rectal Cancer

INTRODUCTION

In patients with locally advanced rectal cancer, restaging pelvis magnetic resonance imaging (MRI) after neoadjuvant concurrent chemoradiotherapy is recommended despite its limited accuracy in predicting pathologic T (ypT) and N (ypN) stage. Neoadjuvant rectal (NAR) score is a novel short-term surrogate endpoint for disease-free survival (DFS) and overall survival (OS). We tested the agreement between restaging MRI T (yT) and N (yN) with ypT and ypN stages, respectively, and explored the prognostic significance of restaging MRI NAR (mNAR) score.

PATIENTS AND METHODS

Between 2014 and 2018, 43 patients with locally advanced rectal cancer completed neoadjuvant concurrent chemoradiotherapy, had a restaging MRI, and underwent surgery. Weighted kappa was used to test the agreement between yT and yN with ypT and ypN, respectively. A kappa value of less than 0.5 was deemed unacceptable. Paired t test was used to compare NAR and mNAR mean scores. Survival was estimated by Kaplan-Meier curves.

RESULTS

Restaging MRI could not predict ypT stage (slight agreement, κ = 0.111) or ypN stage (fair agreement, κ = 0.278). The mean mNAR score was higher than the mean NAR score (20 vs. 16, P = .0079). The median DFS for patients with low-intermediate NAR and high NAR was not reached vs. 30 months (P = .0063). The median OS for patients with low-intermediate NAR and high NAR was not reached vs. 40 months (P = .0056). There was a trend for longer DFS and OS in patients with low-intermediate mNAR scores (not reached in both groups, P = .058) compared to patients with high mNAR scores (not reached in both groups, P = .15).

CONCLUSION

Restaging MRI could not predict ypT and ypN stage. The mean mNAR score was higher than the mean NAR score. There was a trend for longer DFS and OS in patients with low-intermediate mNAR scores compared to patients with high mNAR scores.

Exosomal marker CD63 expression pattern using immunohistochemistry (IHC) in patients with rectal adenocarcinoma in comparison with left-sided colon cancer

e16096

Background: Adenocarcinomas arising from the distal one third of the transverse colon, splenic flexure, descending colon, sigmoid colon and rectum are often grouped together due to their hindgut embryologic origin and referred to as left-sided colorectal cancer (CRC). Rectal cancer represents a subset of CRC that has distinct differences in anatomical location, clinical behavior, prognosis and molecular background. In patients with left sided colon cancer (LSCC), the expression of exosomal marker CD63 was reported to be higher in the adjacent normal mucosa (ANM) compared to the tumor (224 vs 154, p = 0.0001). Here, we explored the pattern of CD63 expression using immunohistochemistry in patients with rectal cancer in comparison with patients with LSCC. Methods: Between 2015 and 2018, 53 patients underwent rectal cancer biopsy/resection and had available tissues for CD63 IHC staining. Two pathologists independently scored CD63 expression in the tumor and ANM. Staining intensity was graded from 1-3. Staining percentage was estimated in 10% increments. Mean quick-score (Q-score) was calculated (intensity x percentage). Paired t test was used for statistical analysis. Results: Median age was 60 (range 34-80). Females represented 26%. Caucasians and African Americans represented 74% and 26%, respectively. In patients with rectal cancer, the mean CD63 expression was higher in ANM compared to their expression in the tumor (147 vs 113, p = 0.0012). Compared to patients with LSCC (N = 30), the mean CD63 expression in patients with rectal cancer was lower in the ANM (224 vs 147, p < 0.0001) and in the tumor (154 vs 113, p = 0.01). Conclusions: In our cohort of patients with rectal cancer, exosomal marker CD63 expression was lower in tumor compared to ANM. This observation was similar to our previously reported findings in patients with LSCC. Compared to patients with LSCC, patients with rectal cancer had lower expression of CD63 in the tumor and ANM. To our knowledge, this is the first study to explore exosomal marker CD63 expression using IHC in patients with rectal cancer.

Exosomal markers (CD63 and CD9) expression and their prognostic significance using immunohistochemistry in right-sided and left-sided colon cancer

182

Background: Exosomes play pivotal roles in cancer progression, metastasis and chemoresistance. CD63 and CD9 are widely accepted exosomal markers. Their pattern of expression and prognostic significance in patients with RSCC and LSCC is unknown. This study explored CD63 and CD9 expression and prognostic significance in patients with RSCC and LSCC using immunohistochemistry (IHC). Methods: Between 2015 and 2018, 63 patients underwent surgical resection of colon cancer for whom we had available tissues for CD63 and CD9 IHC staining. Two pathologists independently scored the CD63 and CD9 expression in the tumor and adjacent normal mucosa (ANM). Staining intensity was graded 1-3 and staining percentage was estimated in 10% increments. Mean Quick-score (Q-score) (intensity X percentage of staining) was calculated. Results: RSCC and LSCC represented 52% and 48% of the patients respectively. The ANM and Tumor CD63 Q-scores were 225 vs 191 (p = 0.009) in RSCC and 224 vs 154 (p = 0.0001) in LSCC, respectively. The ANM and Tumor CD9 Q-scores were 134 vs 152 (p = 0.142) in RSCC and 135 vs 154 (p = 0.137) in LSCC, respectively. In patients with RSCC and LSCC, the mean Tumor CD63 Q-score was 191 vs 154 (p = 0.024), while the mean ANM CD63 Q-score was 225 vs 224 (p = 0.920). The mean Tumor CD9 Q-score was 152 and 154 (p = 0.883), and the mean ANM CD9 Q-score was 134 vs 135 (p = 0.926). In our cohort, there was no difference in progression free survival (PFS) between patients with RSCC and LSCC (p = 0.2349). In all patients, there was no difference in PFS in patients with CD63 expression < 100 and ≥100 (p = 0.8284). Among patients with RSCC, there was a significantly lower PFS in patients with CD63 expression < 100 vs. ≥100 (p = 0.0259). However, among patients with LSCC, there was no difference in PFS in patients with CD63 expression < 100 vs. ≥100 (p = 0.3494). Conclusions: To our knowledge, this is the first study to show a difference in exosomal marker (CD63) expression pattern and its prognostic significance in patients with RSCC and LSCC. There was a significant positive correlation between progression free survival in patients with RSCC and higher exosomal expression.

The prognostic significance of magnetic resonance imaging (MRI) following neoadjuvant concurrent chemoradiation (NCCR) in patients with locally advanced rectal adenocarcinoma (LARA)

e15166

Background: In patients with locally advanced rectal adenocarcinoma (LARA), the response to neoadjuvant concurrent chemoradiation (NCCR) correlates with long-term outcomes. Neoadjuvant rectal (NAR) score ([5 ypN - 3 (cT - ypT) + 12]2/9.61) is a novel short-term surrogate endpoint for disease free survival (DFS) and Overall survival (OS). The prognostic significance of magnetic resonance imaging (MRI) findings following NCCR is yet to be explored. Here, we evaluated the agreement between post NCCR MRI yT and yN and pathological ypT and ypN. In addition, we calculated the post NCCR MRI NAR (mNAR) score using the MRI yT and yN ([5 yN - 3 (cT - yT) + 12]2/9.61) and explored its prognostic significance. Methods: Between 2014 and 2018, all patients with LARA were identified. Among those, 43 patients received NCCR, had post NCCR MRI and underwent surgical resection. Weighted Kappa was used to measure the agreement between post NCCR MRI yT and yN and pathological ypT and ypN. Paired t-test was used to compare the means between NAR and mNAR scores. NAR and mNAR scores were classified as low ( < 8), intermediate (8-16) and high ( > 16). DFS and OS were analyzed using Kaplan-Meier curves. Results: In our cohort, the agreement was slight between post NCCR MRI yT and Pathological ypT (p = 0.111), and fair between post NCCR MRI yN and pathological ypN (0.278). The mean NAR score was 16 and the mean mNAR score was 20 (p = 0.0079). Low-intermediate and high NAR scores were seen in 31 (72%) and 12 (28%) patients respectively. However, low-intermediate and high mNAR scores were seen in 20 (47%) and 23 (53%) patients respectively. The median DFS in patients with low-intermediate and high NAR scores was not reached and 30 months (p = 0.00063) respectively. The median OS in patients with low-intermediate and high NAR scores was not reached and 40 months (p = 0.00056) respectively. The median DFS in patients with low-intermediate and high mNAR scores was not reached in both groups (p = 0.058). The median OS in patients with low-intermediate and high mNAR scores was not reached in both groups (p = 0.15). Conclusions: Post NCCR MRI yT and yN had slight and fair agreements with ypT and ypN respectively. In our cohort, there was a difference between NAR and mNAR. NAR demonstrated prognostic significance for DFS and OS, while mNAR did not at the time of analysis.

Exosomal markers (CD63 and CD9) expression using immunohistochemistry (IHC) in patients with right-sided and left-sided colon cancer

e15119

Background: Embryologically, the right colon (cecum, ascending colon, hepatic flexure and proximal two-thirds of the transverse colon) is derived from the midgut, whereas the left colon (sigmoid colon, descending colon, splenic flexure and distal third of the transverse colon) is derived from the hindgut. There are clinical, pathological and molecular differences between patients with right-sided colon cancer (RSCC) and left-sided colon cancer (LSCC). Exosomes mediate intercellular communications and interactions and have pivotal roles in cancer behavior. CD63 and CD9 are widely accepted exosomal markers. Here we explored CD63 and CD9 expression using immunohistochemistry (IHC) in patients with RSCC and LSCC. Methods: Between 2015 and 2018, 63 patients underwent colon surgical resection for whom we had available tissues for CD63 and CD9 IHC staining. Two pathologists independently scored CD63 and CD9 expression in the tumor and adjacent normal mucosa (ANM). Staining intensity was graded from 1-3. Staining percentage was estimated in 10% increments. Mean quick-score (Q-score) was calculated (intensity x percentage). Unpaired t test was used for statistical analysis. Results: Median age was 64 (range 33-78). Females represented 60% of our cohort. Caucasians, African Americans and other Ethnicities represented 55%, 40% and 5% respectively. The sidedness was designated as RSCC in 52% and as LSCC in 48%. The ANM and Tumor CD63 Q scores were 225 vs 191 (p = 0.009) in RSCC and 224 vs 154 (p = 0.0001) in LSCC respectively. The ANM and Tumor CD9 Q scores are 134 vs 152 (p = 0.142) in RSCC and 135 vs 154 (p = 0.137) in LSCC respectively. In patients with RSCC and LSCC, the mean Tumor CD63 Q score is 191 vs 154 (p = 0.024), while the mean ANM CD63 Q score is 225 vs 224 (p = 0.920). The mean Tumor CD9 Q score is 152 and 154 (p = 0.883) and the mean ANM CD9 Q score is 134 vs 135 (p = 0.926). Conclusions: In our cohort of patients with RSCC and LSCC, the exosomal marker CD63 expression is lower in the tumor compared to the ANM. While ANM CD63 expression was similar between RSCC and LSCC, tumor CD63 expression was higher in RSCC compared to LSCC. The exosomal marker CD9 was not found to have significant differential expression between ANM and tumor and between RSCC and LSCC. To our knowledge, this is the first study to explore exosomal markers expression using IHC in patients with RSCC and LSCC.

MitoVitE, a mitochondria-targeted antioxidant, limits paclitaxel-induced oxidative stress and mitochondrial damage in vitro, and paclitaxel-induced mechanical hypersensitivity in a rat pain model

BACKGROUND

Neuropathic pain is a common side-effect of chemotherapy. Although precise mechanisms are unclear, oxidative stress and mitochondrial damage are involved. We investigated whether the mitochondria targeted antioxidant, MitoVitE, provided better protection against paclitaxel-induced mitochondrial damage in rat dorsal root ganglion (DRG) cells, than a non-targeted form of vitamin E, Trolox. We also determined whether MitoVitE, compared with duloxetine, could limit paclitaxel-induced mechanical hypersensitivity in rats.

METHODS

Mitochondrial function was measured in DRG cells exposed to paclitaxel with and without MitoVitE or Trolox. The effect of MitoVitE or Trolox on paclitaxel-induced cell killing in cancer cell lines was also determined. Rats received a cumulative dose of 8 mg kg^-1 paclitaxel plus either MitoVitE (2 mg^-1 kg day^-1), duloxetine (10 mg kg^-1 day^-1) or vehicle control daily. Mechanical hind paw withdrawal thresholds were measured every two days.

RESULTS

Paclitaxel caused loss of membrane potential in DRG cells. At 100 µM paclitaxel median [range] change was 61[44-78]%, P < 0.0001, which was ameliorated by MitoVitE (86[62-104]%) but not Trolox (46[46-57]%). Similarly, loss of metabolic activity and glutathione induced by paclitaxel (both P < 0.0001) were reduced by MitoVitE but not Trolox. Cytotoxicity of paclitaxel was not affected by co-exposure of ovarian cancer cells to either MitoVitE or Trolox, but was slightly reduced against breast cancer cells, in the presence of Trolox. Mean (SD) areas under the curve of withdrawal thresholds at 6 h after injection in rats given paclitaxel + control, or + MitoVitE (P < 0.0001) or + duloxetine (P < 0.0001) were 110 (5), 145 (10) and 156 (13) respectively.

CONCLUSIONS

Paclitaxel affected mitochondrial function and glutathione in DRG cells, which was abrogated by MitoVitE but not Trolox, without decreasing cancer cell cytotoxicity. In rats, paclitaxel-induced mechanical hypersensitivity was ameliorated by MitoVitE treatment to an extent similar to duloxetine. These data confirm mitochondria as a mechanistic target for paclitaxel-induced damage and suggest mitochondria targeted antioxidants as future therapeutic strategies.

Examining the relationship between socio-economic status, WASH practices and wasting

Childhood wasting is a global problem and is significantly more pronounced in low and middle income countries like Bangladesh. Socio Economic Status (SES) and Water, Sanitation and Hygiene (WASH) practices may be significantly associated with wasting. Most previous research is consistent about the role of SES, but the significance of WASH in the context of wasting remains ambiguous. The effect of SES and WASH on weight for length (WHZ) is examined using a Structural Equation Model (SEM) to explicitly describe the direct and indirect role of WASH in the context of SES.A nationally representative survey of 10,478 Bangladeshi children under 5 were examined. An expert defined SEM was used to construct latent variables for SES and WASH. The SEM included a direct pathway from SES to WHZ and an indirect pathway from SES to WHZ via WASH along with regression of relevant covariates on the outcome WHZ and the latent variables. Both SES (p<0.01) and WASH (p<0.05) significantly affect WHZ. SES (p<0.01) also significantly affects WASH. Other structural components showed that child's age (p<0.01) affects WHZ and types of residence (p<0.01) affects SES. WASH practices at least partially mediate the association between SES and wasting status. WASH and SES are both significantly associated with WHZ.

Use of a pathway quality improvement care bundle to reduce mortality after emergency laparotomy

Background

Emergency laparotomies in the UK, USA and Denmark are known to have a high risk of death, with accompanying evidence of suboptimal care. The emergency laparotomy pathway quality improvement care (ELPQuiC) bundle is an evidence-based care bundle for patients undergoing emergency laparotomy, consisting of: initial assessment with early warning scores, early antibiotics, interval between decision and operation less than 6 h, goal-directed fluid therapy and postoperative intensive care.

Methods

The ELPQuiC bundle was implemented in four hospitals, using locally identified strategies to assess the impact on risk-adjusted mortality. Comparison of case mix-adjusted 30-day mortality rates before and after care-bundle implementation was made using risk-adjusted cumulative sum (CUSUM) plots and a logistic regression model.

Results

Risk-adjusted CUSUM plots showed an increase in the numbers of lives saved per 100 patients treated in all hospitals, from 6·47 in the baseline interval (299 patients included) to 12·44 after implementation (427 patients included) (P < 0·001). The overall case mix-adjusted risk of death decreased from 15·6 to 9·6 per cent (risk ratio 0·614, 95 per cent c.i. 0·451 to 0·836; P = 0·002). There was an increase in the uptake of the ELPQuiC processes but no significant difference in the patient case-mix profile as determined by the mean Portsmouth Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity risk (0·197 and 0·223 before and after implementation respectively; P = 0·395).

Conclusion

Use of the ELPQuiC bundle was associated with a significant reduction in the risk of death following emergency laparotomy.

Oxalate nephropathy: An important cause of renal failure after bariatric surgery

Obesity is a major public health issue all over the world. Bariatric surgery is increasingly becoming popular as a surgical treatment for morbid obesity. Nephrologists need to be aware of possible renal complications after bariatric surgery. We report a 54-year-old male patient who presented with progressive worsening of renal function following a duodenal switch procedure for morbid obesity, and he was found to have oxalate nephropathy on renal biopsy.

P5-14-13: Favorable Prognosis in Patients with T1a,b Node-Negative Triple Negative Breast Cancers Treated with Multimodality Therapy

Purpose: To evaluate the clinical characteristics, natural history and outcomes in patients with ≤1cm, node-negative triple negative breast cancer (TNBC).

Materials and Methods: After excluding patients who received neoadjuvant therapy, 1,022 TNBC patients who received definitive breast surgery from 1999 to 2006 were identified from an institutional database. Among these, 194 patients had node-negative tumors ≤1cm and comprise the study population. Clinical data was abstracted and survival outcomes were analyzed.

Results: Median follow-up time was 71 months (range 2–143). Median age at diagnosis was 55.5 years (range 27–84). T stage was T1mic in 16 (8.2%), T1a in 49 (25.3%), T1b in 129 (66.5%). The majority of tumors were poorly differentiated (N= 142, 73%), lacked lymphovascular invasion (N= 170, 87.6%) and were screening-detected (69%, N=134). Breast-conserving surgery (BCS) was employed in 129 (66.5%) and mastectomy in 65 (33.5%) patients. 113 (58%) patients received adjuvant chemotherapy and 123 (63%) received whole breast radiation. Patients who received chemotherapy tended to have more adverse clinical and disease features (younger age,T1b, poor tumor grade; all p&lt;0.05). For the entire group, 5 year local recurrence-free survival was 96% and distant metastasis-free survival was 95%, with no difference in distant relapse rates between T1mic/T1a vs. T1b patients (94.5% vs 95.5%, p=0.81 )or by receipt of chemotherapy (95.9% vs 94.5%, p=0.63).

Conclusion: Excellent 5-year locoregional and distant control rates were achievable in patients with TNBC tumors ≤ 1.0 cm, 58% of whom received chemotherapy. These results identify a group of TNBC patients with favorable outcomes following early detection and multimodality treatment.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P5-14-13.